Synthesis and Spectroscopic Characterization of Potassium Polyfluoroalken-1-yltrifluoroborates

Abstract

The potassium fluoroborates K[RCF=CFBF 3 ] (R = F, Cl (cis-/trans-mixture), trans-C 4 F 9 , cis-C 2 F 5 , cis-C 6 F 13 , trans-C 4 H 9 , trans-C 6 H 5 ) were prepared by fluoridation (methoxide-fluoride substitution with K[HF 2 ]) of RCF=CFB(OMe) 2 and Li[RCF=CFB(OMe) 3 ] which were obtained from RCF=CFLi and B(OMe) 3 . The K[RCF=CFBF 3 ] salts were characterized by their 1 H, 11 B, 19 F NMR and IR spectra.

An efficient stereoselective preparation of cis-perfluoroalkenylzinc reagents [(E)-RFCFCFZnCl] by the metallation of 1H,1H-perfluoroalkanes and their derivatization to cis-1-arylperfluoroalkenes [(Z)-RFCFCFAr]

“…BuLi under conditions similar to that of the metallation of HFC-134a [30,31] at low temperature to produce the corresponding perfluoroalkenyllithium (C 6 F 13 CF CFLi) in a cis-selective fashion (Scheme 3) [64,65]. Here the initially formed intermediate lithium species [C 6 F 13 CF 2 CHFLi] eliminates LiF and leads to the (Z)-C 6 F 13 CF CHF with 95% selectivity, which was then readily consumed by the base to produce the perfluoroalkenyllithium species.…”

“…This prompted us to consider 1H,1H-perfluoroalkanes with even larger R F groups, such as C 4 F 9 , C 5 F 11 , C 6 F 13 , C 10 F 21 for this metallation process. So four 1H,1H-perfluoroalkanes (R F CF 2 CH 2 F, R F = C 4 F 9 , C 5 F 11 , C 6 F 13 , C 10 F 21 ) were prepared from the corresponding alcohol (Scheme 4) [64]. The precursor alcohols (R F CF 2 CH 2 OH) were either commercially available or synthesized by the room temperature reduction of the methyl ester of the corresponding acids (R F CF 2 CO 2 Me) using NaBH 4 [66].…”

“…1 H NMR (CDCl 3 ): d 4.89 (t, J = 12 Hz, 2H).1H,1H-Perfluorooctylnonaflate (23.3 g, 34.2 mmol) was treated with KF (9.9 g, 170.8 mol) in TG (180.0 mL) at 200 8C for 5 h, followed by isolation as per the above procedure to afford 1H,1H-perfluoroheptane as a colorless liquid (9.6 g, 23.9 mmol, 70%)[64] [bp: 131-133 8C].19 F NMR (CDCl 3 ): d À81.4 (t, J = 10 Hz, 3F), À122.6 (m, 4F), À123.3 (m, 4F), À124.2 (m, 2F), À126.6 (m, 2F), À242.2 (tm, J = 46 Hz, 1F). 1 H NMR (CDCl 3 ): d 4.75 (dt, J = 46, 12 Hz, 2H).…”

Electrophilic polyfluoroalkylating agents based on sulfonate esters

“…The preparation of the (perfluoroheptyl)methyl nonaflate utilizes the corresponding fluoride of the sulfonic acid. Thus, (perfluoroalkyl)methyl nonafluorobutanesulfonate, was easily obtained by treating (perfluoroalkyl)methanols with a slight excess of C 4 F 9 SO 2 F in diethylether or dichloromethane in the presence of triethylamine [23,68,69] with high yields (Scheme 5).…”

Photoinduced Isomerization of Potassium Polyfluoroalk-1-enyltrifluoroborates

“…1 D-47048 Duisburg, Germany e-mail: frohn@uni-duisburg.de 1) C 6 F 13 CF 2 CH 2 F was used as starting material for the preparation of K [cis-(C 6 F 13 )CFϭCF(BF 3 )] [2]. Initially we tested the UV irradiation of solutions of K [trans-C 4 F 9 CFϭ CFBF 3 ] 1a in methanol, acetonitrile and acetone using a highpressure mercury lamp (λ Ͼ 280 nm).…”